This invention relates to a novel ultraviolet lamp curing assembly for the curing of radiation-sensitive materials such as ultraviolet curable inks, and more specifically relates to a novel multiple lamp arrangement which can be contained in a relatively small volume and which is relatively simple to manufacture.
Apparatus for producing ultraviolet radiation for the purpose of curing radiation-sensitive materials is well known. This kind of apparatus is described in U.S. Pat. Nos. 3,733,709 to Bassemir et al, 3,745,307 to Peek et al and 3,826,014 to Helding. Devices of this general category focus ultraviolet radiation on a moving web or moving sheet, and are generally provided with some type of shutter means to enable the easy redirection or blocking of ultraviolet radiation from the web without fully shutting off the ultraviolet lamps.
For example, it is necessary to remove ultraviolet radiation from the web if the web stops in order to prevent burning or other damage to the web or to the surrounding structural components of the device due to the intense heat produced by the ultraviolet lamps. It is, therefore, common practice to introduce movable shutters between the ultraviolet lamp and the web and to reduce the power to the lamps without turning them off during these intervals. Power to the lamps is usually not turned off since the lamps must remain off for a relatively long time before they can be reignited after shutdown.
Shutter structures which have been used in the past may be water-cooled radiation blocking and heat absorbing members which are laterally moved between the lamp and the web. Other arrangements are provided which use a clam-shell type of shutter arrangement around the ultraviolet lamp. Still other types of shutter configurations are known where the lamp reflector is simply rotated about the lamp axis, as in U.S. Pat. No. 3,829,982, where the lamp and its reflector are rotatably contained within a suitable shell.
Whenever the shutter components are designed with water-cooling conduits attached thereto to absorb the substantial amounts of heat produced by the lamps when the shutters are closed, a substantial amount of space is required for the shutter members. Moreover, relatively complex operating mechanisms have been needed to operate the shutters in the past and some difficulty has been experienced in applying the cooling liquid to the shutter structures since the shutters execute considerable movement.